Small hand-held data processing devices with display screens are becoming increasingly more common in a wide variety of uses. For example, small hand-held computers commonly called "personal assistants" or "palm held computers" are currently available. Typically, the small hand-held computers have associated with them small display screens. Similarly, communicators having both cellular communication and computer capabilities are available, typically having small display screens. These small, portable devices do not, and cannot, conveniently have conventional input devices, such as a computer mouse and other control buttons/knobs. Therefore, conventional personal computer interfaces, which also have their own problems, are not suited for these small portable devices.
As a result, there are significant limitations on using such small portable devices in both obtaining output, e.g., viewing data on the display screen, and in inputting commands, e.g., changing the area viewed on the display screen or controlling the performance of a particular parameter associated with the device. Further, given the limited area available, not only on the display screen but also on the entire device, adding additional control buttons/knobs, etc., is both difficult and burdensome to a user requiring two hand operation of the device.
The present invention is directed toward overcoming one or more of the above-identified problems.